DESULFUROMONAS THIOPHILA SP-NOV, A NEW OBLIGATELY SULFUR-REDUCING BACTERIUM FROM ANOXIC FRESH-WATER SEDIMENT

A mesophilic, acetate-oxidizing, sulfur-reducing bacterium, strain NZ2 7(T), was isolated from anoxic mud from a freshwater sulfur spring, Th e cells were ovoid, motile, and gram negative, In addition to acetate, the strain oxidized pyruvate, succinate, and fumarate, Sulfur flower could be replaced by polysulfide as an electron acceptor, Ferric nitri lotriacetic acid was reduced in the presence of pyruvate; however, thi s reduction did not sustain growth. These phenotypic characteristics s uggested that strain NZ27(T) is affiliated with the genus Desulfuromon as. A phylogenetic analysis based on the results of comparative 16S ri bosomal DNA sequencing confirmed that strain NZ27(T) belongs to the De sulfuromonas cluster in the recently proposed family ''Geobacteraceae' ' in the delta subgroup of the Proteobacteria, In addition, the result s of DNA-DNA hybridization studies confirmed that strain NZ27(T) repre sents a novel species, Desulfuromonas thiophila, a name tentatively us ed in previous publications, is the name proposed for strain NZ27(T) i n this paper.